Cam



W. BUHL.-

CAM. APPLICATION FILED SEPT. I2, 1-919.

1,349,661. Patented Aug- 17,1920.

.contour consisting,

UNITED STATES PATENT OFFICE.

WILLIAM BUHL, FLUSHING, NEW YORK, ASSIGNOR'TO BULKRUG MACHINE CORPORATION, A CORPORATION OF NEW YORK.

CAM.

Specification of Letters Patent.

Patented Aug. 17, 1920.

, Application filed September 12, 1919. Serial No. 323,332.

To all whom it mag concern.-

Be it known that 1, WILLIAM BUHL, a citizen of the United States, anda resident of for its object to provide a cam member having a cam contour with which is adapted to cotlperate a revolving driving member, the

said driving member operating to effect percussive motion of the cam member, the said cam contour being provided with means whereby, at the end of the percussive stroke or movement of the said cam device, the latter is free from the said driving member.

Other objects and advantages of my invention will be referred to in the *detailed description thereof which follows or will be apparent from such description. In order that my invention may bereadily understood and its practical advantages fully appreciated, reference may be had to the accompanying drawing in which I have illustrated one convenient form of embodiment thereof.

In the dra wing:

Figure 1 is a view in side elevation of a. cam device rovided with a cam contour constructed 1n accordance with my invention and showing also a portion of a connection leading to a hammer or other tool or member, and also showing a revoluble means for driving the said cam device; and

Fig. 2 is a diagram illustrating the move- 7 ments of the cam device eifected by the revolution of the said driving means situated in the said cam contour.

Referring tothe drawing: 1 cam device or member provided with a cam in the construction shown, of a slot, one portion 2 of which is of arcuateyshape, while another portion '3. thereof is straight and ,may be described as beingin tan ential relation with respect to the arcuate s ape'd portion 2.

The straight portion 3 may be of any length desired and instead of terminating with the edge of the cam device or member 1,, as is shown at 4 in Fig. 1, said straight portion of the slot may be extended to and through the end of said member. Such construction, however, would unnecessarily weaken the cam member 1 and consequently "the cam device or member 1.

the latter would usually be selected of a size to permlt the provision of a straight portion 3 wholly within the same, of such length as might be found to be desired or required.

The straight portion3 of the cam slot constitutes the upper portion of said slot. The lower end of said portion is indicated by the horizontal dot and dash line 11-?) in Fig. 1,

a short distance below the points of contact of the said pin with the slot at the moment of completion ofthe locking movement of t It is at this moment that the impact of the hammer or other tool or member should take place.

The cam device or member 1 which is provided with a connection partially indicated at 5 for connecting it with a hammer or other member'or device is adapted to be actuated by the reciprocating percussive mo tion of the said cam device or member.

V The cam device or member is driven? by means of a crank pin 10 rigidly secured upon the revoluble disk 11. Said crank pin projects into the cam slot, comprising the I parts 2 and 3, and the cylindrical sleeve 12 thereon engages the opposite sides of the arcuate shaped portion 2 of the said cam.

slot. The disk 11 revolves with uniform speed.

Revolution of the crank pin eflects pereussive 'ori quick-return motion of the cam device or member 1 'to effect percussive action of the hammer or other member connected therewith.

The relative speeds of movement of'the cam member 1 resulting from the revoluble N movement of the crank pin 10 in the cam slot 1. thereof are indicated in Fig. 2. Assuming that the crank pin occupies'the position indesignates a dicated at 1 at the right hand side of said figure, which is. the position it occupies at the moment of impact, and that'the crank disk and pin are revolving in the direction of the hands of a clock, it will be. noted that movement of the crank pin on the dot and dash circle 14 from the point 1 to the point 2 causes vertical, upward movement-of the cam device from the point 1 to the oint 2, indicatedon the straight, vertical 0t and dash line 15. Relatively slow vertical, upward movement of the cam device or memberl continues to the point 9 upon said line 15 during movement of the crank pin along the circle 14 to the point 9 thereon. Further movement of the crank pin to the right cam contour.

from the point 9 on the circle 14 causes vertical movement downward of the cam member from the point 9 on the line 15 first to point 10, then to the point 11, then to. point 12, and finally to the point 1 thereon,- the entire vertical downward movement taking place during a movement of the crank pin 10 through a distance of substantially one third of a revolution. The complete vertical upward movement of the cam member is effected during the movement of the crank pin through the remaining two-thirds of a revolution.

It will be seen, therefore, that the cam member together with any tool or other member actuated thereby is moved with relatively great speed downwardly and with relatively slow speed in the opposite direction.

In the construction shown, the cam contour consists of a slot through the cam device or member 1 which is so proportioned and related with respect to the crank pin 10 that at the moment of impact or percussion of the hammer or other member actuated by said device, the said crank pin 10 and sleeve 12 thereon are situated slightly within the lower end of the straight portion 3 of said The result is that at such moment the crank pin is wholly free from and is in released relation with respect to the said cam deviceor member 1. In consequence of this released relationship at this particular moment, the crank pin is not subjected to the reaction effects of the impact of the hammer or other tool or member. The result is that a great deal of jarring and jolting due to the impact of the hammer or other tool or member is eliminated. The said cam member being free to move independently of the said crank pin, the vibrat1ons of the former are not interfered with by the latter, and consequently the effect of the vib ations of the hammer or other tool or member upon the apparatus in which the said cam device or member and hammer or other member are embodied is reduced to a minimum. 1

In Fig. 1 I have shown the crank pin and sleeve in dotted lines well within the straight part 3 of the slot to indicate that there may be relatively great relative, independent movement of the cam device 1 and said crank pin and sleeve in case the cam device and hammer or other member operated thereby should move through an abnormal distance downwardly.

It will be seen that I have provided a cam construction by the employment of which a percussive effect such as a hammer blow can be effected. Such a percussive effect can be produced only b the employment of an elastic system. X non-elastic system produces a squeezing or pressing efiect.

As far as I am aware, these mechanisms 'cussive effect comprise in their a perconstruction an elastic element such as a spring or an air cushion. All attempts heretofore made to produce a percussive effect with a non-elastic mechanism have failed. Those elastic mechanisms which employ springs and air cushions are elastic through the whole cycle of the percussive motion. At the moment of striking the blow in such mechanisms, the percussive effect is restrained to a considerable extent by the dampening effect of the spring or air cushion, whichever may be employed. The ideal mechanism of this type should produce a sling-shot effect; that is, the hammer or other member should be positively driven up to the moment of striking, but at such moment the said hammer or other member should be wholly unrestrained. A cam constructed in accordance with my invention. complies with these ideal requirements of positive driving by non-elastic means except at the moment when the blow is struck. At or during this brief period of time, the driven member is wholly released from the driving member and thereafter the percussive effect is wholly unrestrained. A cam device constructed in accordance with my invention may be employed in mechanism designed for numerous and various purposes, as for instance, in riveting, chipping and calking hammers, hammer-type rock drills, shaking and impact screens, c011- veyers of the shaking trough type, concentrating tables, etc.

I claim:

l. A cam member provided with a. cam contour, said cam contour consisting of an arcuate part adapted to convert uniform rotary motion into rectilinear quick-return motion, and a straight part adjoining one end of the said arcuate part and constituting a continuation of said cam contour.

2. A cam member provided with a cam contour comprising a curved part proportioned to translate rotary crank. motion into percussive reciprocating motion and also comprising a part at one end which is continued in a direction tangent to the adjoining end of the curved part and parallel to the path of movement of said cam memher.

3. A cam member provided with a cam contour comprising a quadrantal shaped part proportioned to translate uniform rotary crank motion into percussive reciprocating motion, and a part continued from one end of the said quadrantal-shaped part in a straight cam path which is adapted to relcase a crank from percussive re-action at the end of the stroke of said cam member.

i. A cam member provided with a cam contour comprising a quadrantal shaped part proportioned to translate uniform rotary in the prior art that actually produce motionand a straight portion situated at the impact end of the stroke ofrsaidca'm member, said straight part being continued as a tangent cam path parallel to the path of reciprocating motion of the cam member.

5. A cam member provided with a cam contour which is adapted to be engaged by a rotary driving member which is adapted to move with uniform speed, the said contour comprising an arcuate part proportioned to translate the motion of said rotary driving member into rectilinear reciprocating motion, and a straight part, the latter part adjoining the upper end of the former part and constituting a continuation of the said cam contour in the direction of the rectilinear reclprocatlng motion of the Sand cam member.

6. A cam member provided with a cam slot adapted to be enga ed by a revoluble driving member, the sai cam slot comprisof the driving member, the said second named portion being situated at one end of said arcuate portion and constituting a continuation thereof.

In testimony that r claim the foregoing as my invention, I have hereunto signed my name this 26th day ofAu ust A. D.; 1919. I WI LIAM BUHL. 

